Can Common Pleco and Common Synodontis (False Upside Down Catfish) Live Together?

Not Recommended

Common Pleco and Common Synodontis (False Upside Down Catfish) are not recommended as tank mates due to slime coat eaters target slow-moving fish, causing severe stress and health issues.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Common Pleco

Hypostomus plecostomus

Common Synodontis (False Upside Down Catfish)

Synodontis nigrita

🐟Family Group
Common Pleco
Catfish
Common Synodontis (False Upside Down Catfish)
Catfish
Temperament
Common Pleco
Mostly Peaceful (4/10)
Common Synodontis (False Upside Down Catfish)
Mostly Peaceful (4/10)
Temperature
βœ“ Compatible
Common Pleco
20–28Β°C
Common Synodontis (False Upside Down Catfish)
22–28Β°C
pH Range
βœ“ Compatible
Common Pleco
6–8
Common Synodontis (False Upside Down Catfish)
6.5–8
Hardness (dGH)
βœ“ Compatible
Common Pleco
4–15
Common Synodontis (False Upside Down Catfish)
5–20
Water Type
βœ“ Compatible
Common Pleco
Freshwater Only
Common Synodontis (False Upside Down Catfish)
Freshwater Only
Flow Preference
βœ“ Compatible
Common Pleco
Moderate
Common Synodontis (False Upside Down Catfish)
Moderate
Min Tank Volume
Combined: 500 L
Common Pleco
500 L
Common Synodontis (False Upside Down Catfish)
200 L
Swimming Level
Shared: 1 zone
Common Pleco
Bottom
Common Synodontis (False Upside Down Catfish)
Bottom
🏷️Behavior Tags
Common Pleco
NocturnalPlant DestroyerSlime Coat Eater (Attacks Flat Fish)Territorial (Defends specific area)
Common Synodontis (False Upside Down Catfish)
NocturnalPiscivore (Eats small/nano fish)Shy / Slow Moving (Easily Stressed)Territorial (Defends specific area)
Stocking calculator

Can your tank handle Common Pleco and Common Synodontis (False Upside Down Catfish)?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Common Pleco
Common Synodontis (False Upside Down Catfish)
Test both in my tank

Behaviour & Temperament

Both Common Pleco and Common Synodontis (False Upside Down Catfish) are generally mild-mannered species with an aggression score of 4/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Common Pleco and Common Synodontis (False Upside Down Catfish) both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

There is a critical concern: the Slime Coat Eater (Attacks Flat Fish) behaviour of one fish directly conflicts with the Shy / Slow Moving (Easily Stressed) trait of the other β€” slime coat eaters target slow-moving fish, causing severe stress and health issues..

Additional behavioural considerations to keep in mind: Two territorial species may clash over territory, especially in smaller tanks.

Worth noting: Common Pleco is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

Water Parameters

The safe temperature window for both species falls between 22Β°C and 28Β°C. Aim for the midpoint of this range (around 25.0Β°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Common Pleco and Common Synodontis (False Upside Down Catfish) together, plan for an aquarium of at least 500 litres with a minimum length of 150 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels), Sand (Sifters). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Common Pleco and Common Synodontis (False Upside Down Catfish).

Frequently Asked Questions

Can Common Pleco and Common Synodontis (False Upside Down Catfish) live together?

No. This combination is not recommended. Key incompatibilities β€” such as critical behavioural conflicts β€” make cohabitation unsafe.

What size tank do Common Pleco and Common Synodontis (False Upside Down Catfish) need?

A minimum of 500 litres (tank length at least 150 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Common Pleco and Common Synodontis (False Upside Down Catfish) together?

Keep the aquarium between 22Β°C and 28Β°C. A target of around 25.0Β°C sits comfortably within both species' preferred ranges.

Are Common Pleco or Common Synodontis (False Upside Down Catfish) aggressive?

Common Pleco is generally mild-mannered (4/10) and Common Synodontis (False Upside Down Catfish) is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Common Pleco and Common Synodontis (False Upside Down Catfish) need?

Both species overlap in the 6.5–8 pH range. Consistency is key β€” avoid sudden swings, and test regularly to stay within this window.

How do I manage Common Pleco's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Common Pleco space to claim a territory without encroaching on the other fish's area. Adding dΓ©cor that divides the tank into distinct zones works especially well.

Does Common Pleco being nocturnal affect compatibility?

Common Pleco is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Common Pleco during evening hours.


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